Tape data assessment

ABSTRACT

A method for certifying data on tape cartridges for a library with a first tape cartridge that possesses a medium auxiliary memory device, a medium auxiliary memory reader/writer, a first tape drive and a second tape drive, a shelf system, and access to a memory device containing a media lifecycle management data base. After a period of time from when data was originally stored on the tape first cartridge, a portion of data residing on the first tape cartridge is read. The portion of data is assessed as to whether a percentage of the portion contains an expected data structure and if the percentage exceeds a predetermined threshold, a data recovery sequence is initiated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalPatent Application No. 61/170,046 entitled: Tape Cartridge Verification,filed on Apr. 16, 2009, the entire disclosure of which is herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to tape libraries usingauxiliary memory devices contained in tape storage cartridges tomaintain information related to tape cartridge verification.

2. Description of Related Art

Data storage libraries, such as tape libraries, are typically used tostore and retrieve large amounts of data for data manipulation andarchiving purposes. These libraries are generally comprised of drivedevices adapted to write data to and read data from tape cartridges thatare often housed within the tape libraries. In the interest of obtainingcursory information about a specific tape cartridge without requiring atime-consuming media load and tape threading process to read the on-tapeindex file, techniques using holes arranged in patterns in the cartridgecasing and later electrical pads grounded in a variety of combinationswere introduced. The holes and/or electrical pads provided simpleinformation such as the tape capacity and the manufacturer identity.Today, these techniques are yielding to the introduction of radiofrequency chips located in the tape cartridges, called aMemory-In-Cartridge (MIC) also known as a Medium Auxiliary Memory (MAM).FIG. 1A shows an example of a tape cartridge 100, tape medium 102, andMAM 104 (shown here in dashed lines) The MAM 104 and tape medium 102reside in the interior of the cartridge 100. In this example, the MAM isdisposed in an LTO-3 cartridge which can be provided by TDK Corp. ofTustin, Calif.

A MAM allows the tape drive to access valuable cartridge data withoutthe use of a physical connection, reducing connector wear for both thedrive and the media. The MAM comprises a memory chip built into the datacartridge that provides a direct and immediate connection to the drive'son-board processors, which speeds access to information related to thedata cartridge such as system logs, for example. Information and filesearch parameters are formatted within the MAM system therebyeffectively cutting the data access time down to a fraction fromhistorical techniques.

As shown in FIG. 1B, a MAM 104 fundamentally comprises an integratedcircuit that includes solid state memory and a transponder 124 attachedto an antenna 126, which is typically a small coil of wires. The MAM 104is considered a passive device because it is energized when subjected toa sufficiently strong RF field, generated by a MAM-Reader. Informationcan be transmitted between the MAM and the MAM-Reader via a specificradio frequency.

Though a MAM is capable of storing data, the amount of data stored on aMAM is relatively miniscule compared to that stored on the tape medium102. As such, a MAM device, in the exemplary configuration, cannotreasonably function as a backup device that stores duplicate data storedon the tape medium 102. Currently, data verification on a tape medium isdone by comparing the data stored on a tape medium 102 with a duplicatecopy stored on either a different tape medium or another storage device,such as a disc drive. Hence, if data is corrupt or missing because ofdamage to the tape medium, such as delamination of the magnetic thinfilm from the polymer tape substrate, damage due to contamination, orsome other malfunction, knowledge of data corruption can be accomplishedby comparing the data with the copy of the data. Unfortunately,maintaining a duplicate copy of data for the purposes of dataverification is a resource-consuming approach.

In an effort to expand capabilities of a storage element containing aMAM operable for the purpose of improving data verification of tapecartridges 100, methods and apparatus are disclosed herein. It is toinnovations related to this subject matter that the claimed invention isgenerally directed.

SUMMARY OF THE INVENTION

The present invention relates generally to tape libraries recoveringdata from a failed tape cartridge that are determined failed throughdata assessment analysis. One embodiment of the present inventioncontemplates a method for certifying data on tape cartridges, the methodcomprising: providing a library with: a first tape cartridge possessinga medium auxiliary memory device; a medium auxiliary memory devicereader; a medium auxiliary memory device writer; a first tape drive anda second tape drive; a shelf system; and a system adapted to access amemory device containing a media lifecycle management data base; loadingthe first tape cartridge in the first tape drive; writing new data onthe first tape cartridge after the loading step; recording a firstaccess occurrence corresponding to approximately when the writing stepwas performed; unloading the first tape cartridge from the first tapedrive; disposing the first tape cartridge in the shelf system after theunloading step; loading the first tape cartridge in one of the first orthe second tape drives after a predetermined time has elapsed from thefirst access occurrence; reading a portion of all of the data residingon the first tape cartridge wherein the portion in less than all of thedata; assessing the a percentage of the portion containing an expecteddata structure, wherein the assessing is essentially devoid of datacontent analysis; and initiating a data recovery sequence if thepercentage exceeds a predetermined threshold.

Another embodiment of the present invention can therefore comprise amethod for certifying data retained by a tape cartridge in a tapelibrary, the method comprising: reading a portion of the data at ascheduled time; assessing of the degree to which the portion of datacontains an expected data structure; and reporting, via a displaydevice, to an end user if the degree falls below a predeterminedthreshold.

Yet another embodiment of the present invention can therefore comprise amethod for certifying data, the method comprising: providing a librarywith a tape drive and a tape cartridge, the tape cartridge possessestape medium with data retained thereon; loading the tape cartridge inthe tape drive; reading a portion of the data that is less than all ofthe data; assessing a percentage of errors from reading the portion ofdata, wherein the assessing is accomplished without comparing datacontent; and executing a data recovery action of the data if thepercentage of errors exceeds a predetermined threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a prior art pictorial representation of a tape cartridge withan auxiliary radio frequency memory device.

FIG. 1B is a prior art pictorial representation of an auxiliary radiofrequency memory device.

FIG. 2A is an illustration of a tape library arrangement in accordancewith an embodiment of the present invention.

FIG. 2B is an illustration of a populated tape cartridge magazine inaccordance with an embodiment of the present invention.

FIG. 3A-3C are illustrations of a tape cartridge being verified indifferent libraries in accordance with an embodiment of the presentinvention.

FIG. 4 is an illustration an embodiment of a shelf system that comprisesan auxiliary memory reader that can be used in combination with a loadedtape cartridge magazine in accordance with an embodiment of the presentinvention.

FIG. 5 is an illustration of a transport unit and auxiliary memoryreader arrangement in accordance with an embodiment of the presentinvention.

FIG. 6 is a block diagram illustrating a central data base acting as arepository for information pertaining to a plurality of tape cartridgesin a plurality of libraries in accordance with an embodiment of thepresent invention.

FIGS. 7A and 7B are block diagrams illustrating methods to practiceembodiments of the present invention.

FIG. 7C is a block diagram illustrating a portion of tape mediumformatted with streamed data consistent for tape related use.

FIG. 8 is a block diagram of a reporting layout in accordance with anembodiment of the present invention.

FIG. 9 is a block diagram illustrating an alternative method to practicean embodiment of the present invention.

FIG. 10 is a block diagram of two libraries capable of duplicating datawhile assessing a tape cartridge in accordance with an embodiment of thepresent invention.

FIG. 11 is a block diagram of yet another method to practice anembodiment of the present invention.

FIG. 12 shows a commercial embodiment of one T-950 library unit whereinaspects of the present invention can be practiced.

DETAILED DESCRIPTION

U.S. Provisional Patent Application No. 61/170,046 entitled: TapeCartridge Verification, filed on Apr. 16, 2009 is hereby incorporated byreference in the present Provisional United States Patent Application.

Before proceeding with the detailed description, it is to be appreciatedthat the present teaching is by way of example only, not by limitation.The concepts herein are not limited to use or application with aspecific system or method for using MAM devices and Medium LifecycleManagement (MLM) data bases in tape library applications. Thus, althoughthe instrumentalities described herein are for the convenience ofexplanation, shown and described with respect to exemplary embodiments,it will be appreciated that the principles herein may be applied equallyin other types of systems and methods involving determining verificationof tape cartridges.

Referring to the drawings in general, and more specifically to FIG. 2A,shown therein is an illustration of a data storage arrangementconstructed in accordance with an embodiment of the present invention.In what follows, similar or identical structures may be identified usingidentical callouts.

The data storage arrangement illustrated in FIG. 2A can comprise a userof data 202, such as a client, in communication 216 with a data storagelibrary 200. As illustratively shown, the client 202 is in communicationwith the library 200 via the communication path 216 and a libraryinterface device 214, which can be controlled by an independentcontroller (not shown) or a Central Processing Unit 243 (CPU). Thelibrary 200 comprises a plurality of tape cartridges 100 disposed in atape cartridge magazine 206 wherein each of the tape cartridges 100contains an auxiliary radio frequency memory device (not shown), such asthe MAM 104 of FIG. 1B, capable of retaining auxiliary digital data. Inalternative embodiments, the tape cartridges 100 can be disposed onshelves instead of magazines 206, as will be discussed in conjunctionwith FIG. 3A-3C. A MAM device 104 associated with a tape cartridge, suchas the cartridge 100 or 201, for example, may be identified throughoutthe detailed description as element 104 even though it is considered tobe contained by a cartridge and hence may not be viewable in a specificfigure exemplifying embodiments of the present invention. Hence, theidentification of element 104, used herein, is for illustrative purposesconsistent with MAM device 104.

In this embodiment, the library 200 also comprises several tape drives222 and 224, each capable of reading user data from and writing userdata to one of the plurality of tape cartridges 100. User data, herein,is considered data from a source such as the user of data 202 that isintended for storage on the tape medium 102, of FIG. 1A. As shown, eachtape drive 222 and 224 can be associated with a tape drive MAM devicereader and writer 231 and 230, respectively. Each tape drive 222 and 224is further capable of transmitting an access occurrence, such as dateand time when the tape is loaded in a tape drive 222 and 224, to a MAMdevice 104 via the tape drive radio frequency memory device 230, forexample. Access occurrence refers to approximately when a tape cartridgeis loaded in a tape drive, such as tape drive 224, for purposes ofreading or writing data for example (e.g., date and time, or a run timefrom T=0). In addition, load count (e.g., a running sum of each time atape has been loaded in a drive) can be maintained by the MAM device 104disposed in the tape cartridge 201. An example of a loaded tape drive isthe tape cartridge 201 inserted in the tape drive 224 in a cooperatingreading and writing relationship where user data can be stored and readfrom the tape medium 102 contained substantially by the cartridge 201.Reading and writing data to and from a tape medium 102 can also bereferred to as “storage operations”. As shown here, the loaded tapedrive 224 is also in radio frequency communication 223 with the MAMdevice 104, which is associated with tape cartridge 201, via the tapedrive MAM device 230, which is associated with tape drive 224. The tapedrive 224 (as well as 222) is capable of transmitting date and time, orjust date or time, to the MAM device 104 associated with the tapecartridge 201 when data is written to the tape or, optionally, each timethe tape is loaded into the tape drive 224. Data is transmitted to theMAM device 104 via the tape drive MAM device reader and writer 230. Inan optional embodiment, the MAM device reader is a device separate fromthe writer. An auxiliary storage device 240 can accommodate information,such as the access occurrence, from a plurality of MAM devices 104 eachcontained in an associated tape cartridge 100. The access occurrencefrom any MAM device 104 can be compared with the access occurrence fromthe associated tape cartridge 201 as stored in the auxiliary storagedevice 240 via a processor device 241.

The library 200 can further comprise a shelving system 220 capable ofarchiving the tape cartridge magazines 206 within the library 200. Inthis embodiment, the shelving system 220 is associated with one or moreMAM device readers 232 that is at least capable of reading data, such asthe access occurrence information, stored on an MAM device 104 containedby each tape cartridge 100. A transport unit 214 is an example of how atape cartridge magazine 206 is moved from the shelf system 220 to alocation that facilitates a tape cartridge 100 to be inserted in one ofthe drives 222 or 224 to form a cooperating relationship. The transportdevice 214 can optionally be associated with at least one MAM devicereader 234, as shown here. The library 200 also optionally comprises anentry/exit port 204 whereby tape cartridges 100 or tape cartridgemagazines 206 can be transferred between an environment external to thelibrary 200 and an environment internal to the library 200. The MAMdevice readers 232 and 234 are independent of the tape drive MAM device230, that is, devices 232 and 234 are disposed in locations independentof a tape drive, which are not associated with a tape drive. In thisembodiment, the library 200 can accommodate a graphical user interface218 and an auxiliary memory 240, which can be controlled by a memorycontroller (not shown), such as a disk drive or solid state memorydevice, capable of retaining (storing) relevant information related toeach tape 100, such as that which is stored on a MAM device 104. In oneembodiment, the tape cartridges 100 or the tape cartridge magazines 206may be associated with different users of data such that the storagespace in the library 200 is partitioned into two or more parts whereineach part is associated with the different user of data, for example.

General functionality can be controlled in the library 200 by thelibrary Central CPU 243 over the Computer Area Network (CAN) (notshown). The CAN essentially connects all relevant components with theCPU 243. The CPU 243 is equipped with one or more controllers (notshown) coupled to the processor 241 (such as an Intel Pentium seriesprocessor manufactured by Intel Corporation of Santa Clara, Calif.)primary memory (not shown), such as flash memory, RAM, EEPROM, etc,secondary non-volatile memory (not shown), such as a hard disk drive(such as that produced by Seagate Corporation of Scotts Valley, Calif.).General data and algorithms can be maintained on the secondarynon-volatile memory, for example, algorithms/computer instructions,operating systems, applications that run via cooperation with theprocessors, etc. The CPU 143 can further maintain, via the secondarynon-volatile memory, the addresses of the components mapped out for theclient 202 (e.g., tape slot addresses, drive addresses, robot addresses,etc.) to direct operations within the library 200. FIG. 2A isillustrative of basic components used to exemplify certain inventiveembodiments disclosed herein. As one skilled in the art will appreciate,a data storage library will generally include devices and structures notshown in the block illustration of FIG. 2A, such as additionalcontrollers, wiring, cooling systems, switch systems, lighting, protocolbridges, etc. Also, various library systems may contain multiple CPUs ordivide up the functionality via both internal and external appliances,while still remaining within the scope and spirit of the embodimentsdescribed herein.

As one skilled in the art will recognize, the illustration of thelibrary 200 in FIG. 2A shows the primary elements of interest forpurposes of simplicity. As such, certain necessary structures andcomponents for the aforementioned elements to properly function areomitted from the detailed description; however, such integratingstructures and components do exist within the scope and spirit of thepresent invention. For example, in practice, the library 200 includesall of the necessary wiring, user interface panels, plugs, modularcomponents, entry and exit port(s) to introduce (or remove) removablestorage elements into the library 200, fault protectors, uninterruptablepower supplies, processors, busses, robotic transport unit tracks,indication lights, and so on, in order to function as a data storagelibrary.

With reference to FIG. 2B, shown therein are tape cartridges 100supported by a tape cartridge magazine 206. In more detail, a tapecartridge 100, such as an LTO-3 category tape cartridge manufactured byIBM, of Armonk, N.Y., comprises magnetic tape that is capable of storingdigital data written by a compatible drive 220 or 224, such as an LTO-3tape drive manufactured by IBM, when in cooperation to read and writedata (i.e., loaded) with the tape cartridge 201, as shown in FIG. 2A.The tape cartridge magazine 206 is shown populated with a plurality oftape cartridges 100. A tape cartridge 100 can be removed from the tapecartridge magazine 206, as shown by the arrow 250, and inserted into thetape drive 220 or 224 by means of a picker device 502, shown in FIG. 5.Disposed on the tape cartridge magazine 252 is a bar code identifier 254for identifying the tape cartridge magazine 206 which has utility shouldthe tape cartridge magazine 206 be archived in a media pack storagevault externally located from the library 200, for example. In thisembodiment, all tape cartridges 100 contain an MAM device 104, such asan auxiliary radio frequency memory device, however, in alternativeembodiments, some tape cartridges may not contain an MAM device 104. Inanother embodiment of the present invention, the magazine 206 cancomprise a magazine auxiliary memory device 253 that is capable ofcontaining information from at least one of the data cartridges 100 themagazine 252 supports. The magazine auxiliary memory device 253 canreceive information from the MAM devices 104 contained by each tapecartridge 100 via one or more MAM device readers 232 or 234, forexample. Information from the MAM devices 104 can be read andimmediately transmitted to the magazine auxiliary memory device 253, oralternatively, the information of each of the MAM devices 104 can bestored on the auxiliary storage device 240 and then transferred to themagazine auxiliary memory device 253, just to name two examples. In oneembodiment, the magazine auxiliary memory device 253 can possess accessoccurrence information of every tape cartridge 100 associated with themagazine 206, which can serve a redundancy to the auxiliary storagedevice 240, of FIG. 2A.

A MAM device 104, in one embodiment, is an auxiliary radio frequencymemory device, which is parceled into three regions in which data can bestored; a medium device region which contains information such as aserial number, a device region which contains information from the tapedrive such as load count and access occurrence, and a host/vendor uniqueregion wherein information such as history and/or performance datarelated to the cartridge 100 can be stored. Now information in theregions can be added via an address related to the arrangement ofavailable storage space in the auxiliary radio frequency memory deviceor, optionally, the information can be read by an auxiliary memoryreader, such as the reader 230, and reassembled with additionalinformation and stored on the auxiliary radio frequency memory device asthe reassembled version, just to name two examples. In another example,if the storage limit is reached in the auxiliary radio frequency memorydevice, such as the host/vendor data in the host/vendor unique region,the host/vendor data can be read and stored in an auxiliary storagespace, such as the auxiliary memory 240, and the host/vendor uniqueregion purged and made available for new information. In anotherexample, the host/vendor data can be compressed with algorithms todecompress residing in the library 200 or user of data 202, for example.

With reference to FIG. 3A, shown therein is an illustration of a firsttape library 300 and a second tape library 301 possessing a tape drive302 according to some embodiments of the present invention. As shown,the first tape library 300 comprises a tape cartridge 201 possessing anMAM device 104 that maintains access time and the date when loaded in afirst tape drive 224. The first tape drive 224 possesses an auxiliarymemory device reader and writer 230. The library 300 also possesses asecond tape drive 222 with an associated auxiliary memory device readerand writer 231. The second tape drive 222 is shown not loaded with atape cartridge 100. The library 300 also comprises a processing device241 that is linked to both of the first and second tape drives 224 and222 respectively and the auxiliary storage device 240. The first library300 also possesses a graphical user interface 218 linked to theprocessor device 241 and, in one embodiment, the auxiliary storagedevice 240. The first library 300 also provides a shelf system 308wherein tape cartridges 100 are moveably disposed. In one embodiment,the access occurrence associated with the tape cartridge 201 is updatedeach time the medium in a tape cartridge is threaded in a tape drive,such as the drive 224. In some cases, the access occurrence is recordedwhen the tape cartridge 100 has finished recording user data and isready to be ejected. In both cases, when the tape cartridge 201 isloaded in the tape drive 224, the auxiliary memory device reader andwriter 230 transmits an RF signal 223, for example, that records theaccess occurrence, which is, therefore, maintained in the MAM device 104in what can be date and time (time stamp) or a time starting point (T=0)that can be monitored against a clock or other time keeping device. Inanother alternative embodiment, more than one previous access occurrenceis maintained on the MAM device 104, such as just the previous one ortwo access occurrences, or, optionally, the entire history. The accessoccurrence is also transmitted to the auxiliary storage device 240 whereit can be maintained in a Media Lifecycle Management (MLM) data base,stored therein. In one illustrative embodiment regarding a new tapecartridge 100; in the event the new tape cartridge 100 is introduced tothe library 300, associated tape cartridge identification, such as a barcode, is logged into a library memory device, such as the auxiliarystorage device 240, for example. Hence, the access occurrence on a newlyintroduced tape cartridge 100 is stored on the MAM 104 corresponding tothe newly introduced tape cartridge 100 in addition to being stored inthe auxiliary memory device 240. If the access occurrence is read fromthe MAM 104 and information on the MAM 104 indicates that the tapecartridge 100 was from a different library, and the tape cartridge hasno history of being in the library 300, then the tape cartridge'sidentity is logged in the library 300 and the access occurrence isstored both on the tape's MAM 104 and in the auxiliary memory device 240(e.g., when loaded with the tape drive 224 for the first time). In thisexample, the tape cartridge 201 is considered newly introduced into thelibrary 300 and, thus, the access occurrence is written to the MAM 104(exemplified herein as “time”) that is associated with the tapecartridge 201.

In an optional embodiment, the original access occurrence associatedwith an incoming cartridge 100 may also be stored when loaded in a tapedrive. Hence, if the access occurrence on a newly introduced tapecartridge 100 possesses a corresponding time and/or date, the newlyintroduced tape cartridge 100 information stored on its associated MAM104 is retrieved from the MAM 104 and is stored in the auxiliary memorydevice 240. If the information on the MAM 104 differs from the auxiliarymemory device 240 because the tape cartridge has been in a differentlibrary, then the information in the auxiliary memory device can beupdated.

With reference to FIG. 3B, shown therein is the first library 300 andsecond library 301 wherein the tape cartridge is disposed in the secondlibrary 301. The tape cartridge 201 can be introduced to the secondlibrary 301 via the entry/exit port 306. As illustratively shown, thetape cartridge 201 is loaded in the tape drive 302, and the auxiliarymemory device reader and writer 230 is shown transmitting an RF signal310 that writes the present access occurrence to the MAM device 104. Inan optional embodiment, the tape drive 302 does not have to be housed inthe second library 301, but rather, can be a stand-alone drive notassociated with any library.

FIG. 3C illustrates the tape cartridge 201, once again, located in thefirst tape library 300. As shown, the tape cartridge 201 is disposed inthe first tape drive 224. The recorded access occurrence associated withthe tape 201 is read from the MAM device 104 associated with the tapecartridge 201 via the auxiliary memory device reader and writer 230 andtransmitted to the processor device 241 wherein the processor device 241receives the time from the previous access occurrence from the auxiliarystorage device 240 for comparison. Because the access occurrenceretained in the MAM 104 is not identical to the access occurrencemaintained by the auxiliary storage device 240, a miss-compare isdetermined. A miss-compare is when the comparison of items aredissimilar (not the same). The access occurrence can equally bedetermined from the second tape drive 222 via the auxiliary memorydevice reader and writer 231. In one embodiment, the processor device241 generates a user-specified action in response to the numericaldiscrepancy of different access occurrences of record. A user-specifiedaction can be generated and executed by the processor device 241 or,optionally, an alternative device associated with the first library 300may be capable of performing the function. A user-specified action is anaction that is set in motion based on criteria that a user of data 202,or an operator, defines, for example. This criteria can be a thresholdof time that has transpired from an access occurrence, for example,e.g., a time threshold for taking some action when a predeterminedamount of time has passed since the previous access occurrence on thespecific tape cartridge occurred. A user-specified action can furtherinclude preventing the tape cartridge 201 from leaving the library 300,such as by locking down the library 300 by preventing access to theentry/exit port 204, informing an end user, such as the user of data202, that the access occurrence from the auxiliary storage device 240 isnot identical to the access occurrence maintained by the MAM device 104and letting the user of data 202 decide what to do next, disabling anyuser data stored on the tape cartridge 201, such as by eliminatingaccess to an encryption key if the user data is encrypted, for example,or simply activating an audible and/or visual alarm alerting a user ofdata, or other authority, that the tape cartridge 201 has been loaded ina tape drive other than the authorized tape drives 222 and 224associated with the first library 300. In such an event, a notificationis sent to an end user, such as a user of data 202. The notification maybe arranged to contain information that the tape cartridge 201 has beenread by an external tape drive that is not associated with the firstlibrary 300. Such a notification can be viewable on a visual displaydevice, such as a monitor accessible to the user of data 202.Optionally, the notification can be viewable on the graphical userinterface 218 associated with the first library 300.

FIG. 4 illustrates an embodiment of a shelf system 220 that comprises anauxiliary memory reader 232 that can be used in combination with aloaded tape cartridge magazine 206. As illustratively shown inarrangement-A, the tape cartridge magazine 206 is in the process ofbeing moved onto the shelf 220 in the direction of the arrow. Theauxiliary memory reader 232 is shown transmitting an RF field 404 viaMAM device 104 (in this case, an auxiliary radio frequency memorydevice) contained in cartridge A 402. Arrangement-B illustrates the MAMdevice 104 contained in tape cartridge A 302 transmitting data, such asaccess occurrence information relative the history of loads associatedwith cartridge A 402, in the form of an RF signal 406 to the auxiliarymemory reader 232 when positioned in the presence of the RF field 404.In one embodiment of the present invention, the auxiliary radiofrequency memory device 104 is a passive device because it is energizedwhen subjected to a strong enough RF field produced by the auxiliarymemory reader 232. Information is transmitted between the MAM device 104and the auxiliary memory reader 232 via a specific radio frequency,shown here as 404 and 406. Data can be transferred and stored on the MAMdevice 104 from the library 200 or alternatively (and in addition to)data from the MAM device 104 can be transferred to the auxiliary memory240 via the auxiliary memory reader 232. Arrangement-C illustrates theMAM device 104 contained in tape cartridge B 408 transmitting data inthe form of an RF signal 407 to the auxiliary memory reader 232 whenpositioned in the presence of the RF field 404. Arrangement-Dillustrates the MAM device 104 contained in tape cartridge C 410transmitting data in the form of an RF signal 409 to the auxiliarymemory reader 232 when positioned in the presence of the RF field 404.The load information can be further stored on a magazine auxiliarymemory device 253, of FIG. 2B, for every cartridge 100 populated in themagazine 206. In an optional embodiment, the auxiliary memory reader 232can be linked with the processor device 241 and the auxiliary storagedevice 240, thus, providing access occurrence information for comparisonthat can be used as an alternative to the auxiliary memory device readerand writer 230 described in FIG. 3C.

With reference to FIG. 5, shown therein is an illustration of thetransport unit 214, of FIG. 2A, in greater detail. The transport unit214 is adapted to transport tape cartridge magazines 206 within thelibrary 200. A cartridge picker 502, which can be associated with thetransport unit 214, is adapted to move cartridges 100 from a tapecartridge magazine 206 into a cooperating read/write relationship with atape drive, such as tape drive 224 of FIG. 2A. The transport unit 214 isillustratively shown accommodating an auxiliary memory reader 234 thatis transmitting an RF signal 508 (and potentially data) to a MAM device104 contained in tape cartridge D 504 whereby the MAM device 104 ofcartridge D 504 is transmitting data, such as access occurrenceinformation, via an RF signal 510 to the auxiliary memory reader 234. Inan optional embodiment, the auxiliary memory reader 234 can be linkedwith the processor device 241 and the auxiliary storage device 240,thus, providing access occurrence information for comparison that can beused as an alternative to the auxiliary memory device reader and writer230 described in FIG. 3C.

FIG. 6 is a block diagram illustrating a central data base 602 acting asa repository for information pertaining to access occurrences for atleast each tape cartridge associated with libraries A-E 604-612. Asshown in the illustrative arrangement, library A 604, B 606, C 608, D610 and E 612 are each linked to the central data base 602. The centraldata base 602 can provide storage of any, and all, MAM deviceinformation, including all information related to when accessoccurrences took place of all tapes associated with libraries A-E604-612, contained in each tape cartridge associated with each libraryA-E 604-612. The central data base 602 can provide the function of theprocessor device 241 and auxiliary storage device 240 from FIGS. 3A-3C,thus generating a user-specified action if a time threshold has beenreached for the elapsed time from an access occurrence associated with aspecific tape cartridge that is housed in one of the libraries A-E604-612. In other words, all of the tape drives of libraries A-E 604-612are known entities and, therefore, each load occurrence is known on tapecartridges from libraries A-E 604-612. The MAM device information storedon the central data base can be viewed by an authority, such as anOriginal Equipment Manufacturer of libraries and/or tapes, for purposesof tape management.

Time from an access occurrence can be used, among other things, toupdate data, evaluate data or verify data, just to name several uses ofaccess occurrence. In the case involving verifying data, data stored ona tape cartridge 100 may become lost or corrupt over time from damage tothe tape cartridge 100 or tape medium 102 housed therein. For example,the tape medium may stretch over time, may delaminate over time, or maycorrode over time, due to unfavorable environmental conditions, all ofwhich will render the tape medium unreliable for effectively storing ormaintaining data. Some indicators that data maintained on a storagemedium is reliable include predictable data signatures, such as thesignature of the data bits themselves, such as data bit amplitudes andsignal shapes or an expected distribution of 1's and 0's, for example.In other words, reading data for predicted data signatures, as opposedto reading the data for content, is considered a reasonable predictor ofdata integrity. For example, determining data integrity based on thecontent of the data requires some comparison of the data to a known,similar, or duplicate copy of data. For example, an end user generallyrequires that data be read for content (e.g., a Word document). Thecontent in a Microsoft Word document, for example, would be read andunderstood by an end user, however, a predicted data signature of theMicrosoft Word document would be unrecognizable to an end user becauseit would just be an analysis of 1's and 0's, be it amplitude, PulseWidth 50 (PW-50), signal to noise ratio (SNR), data sampled with ErrorCorrection Code (ECC), and the like, just to name several known methodsof analyzing data signatures. Algorithms/programs that assess data inthis way can be maintained in a hard disk drive, or other non-volatilememory, in the CPU 243 executed via a processor/s 241, for example.

Referring now to FIG. 7A, shown therein is a block diagram illustratingmethod steps to practice an embodiment of the present invention. Itshould be recognized that the steps presented in the describedembodiments of the present invention do not necessarily require anyparticular sequence unless otherwise specified explicitly. FIGS. 3A and3B are used in conjunction with FIGS. 7A and B for purposes ofillustration in the present described embodiment. The steps describe anembodiment consistent with the present invention of a method applicableto verifying data on tape cartridges using a cartridge's MAM 104 and anMLM data base which can contain identification information about a tapecartridge, such as a serial number, for example. The MLM data base canbe maintained by an auxiliary storage device 240 as shown in FIGS. 1Aand 2A. Data verification on a tape cartridge will not prove whatcontent is stored on the tape cartridge, but rather, will simply provethat the media is functioning as expected and/or that the data stored onthe tape cartridge is accessible prior to restoring data or storing newdata on the tape cartridge. Performing in an expected manner is toperform according to pre established parameters wherein an end user, forexample, can set the parameters for which the reading performance mustmeet at a minimum.

Step 702 shows a step for providing a library 200 that possesses: afirst tape cartridge 201 possessing a MAM 104, a MAM reader 231, a MAMwriter 231 (in this example the MAM reader and writer are integrated,however, optionally they can be separate devices located separately), afirst tape drive 224, a second tape drive 222, and a shelf system 220.The library 200 has access to a memory device 240 containing an MLMdatabase. The library 200 further includes the elements as discussed inconjunction with FIG. 2A.

Step 704 shows a step for loading the first tape cartridge 201 in thefirst tape drive 224. In the illustrative example of FIG. 2A, the firsttape cartridge 201 is moved via a robot transport unit 214 that, in oneembodiment, can carry a tape cartridge magazine 206 from the shelfsystem 220 to the drives 222 and 224.

Step 706 shows a step for writing new data on the first tape cartridge201 in the first tape drive 224. In an illustrative embodiment, thelibrary 200 receives new data from the user of data 202 (host) andtransmits the new data to the first drive 224.

Step 708 shows a step for recording 223 a first access occurrence on theMAM 104 and on the MLM database maintained by the auxiliary storagedevice 240 wherein the access occurrence corresponds to approximatelywhen the writing step was done. The access occurrence can be the date orthe time, or both date and time, when the data was written. The point intime from when the access occurrence took place can be just prior towriting the data, during when the data is being written, or just afterthe data was written. Optionally, the point in time (time stamp) fromwhen the access occurrence took place can be the day, week, month, etc.Hence, the last access date (occurrence) is stored on the MAM and can,in one embodiment, be overwritten by a new access date. Optionally, timestamps can include when data is read or if a tape cartridge is simplyloaded in a tape drive for some other reason.

Step 710 shows a step for unloading the first tape cartridge 201 fromthe first tape drive 224.

Step 712 shows a step for disposing the first tape cartridge 201 in theshelf system 220 after the unloading step. The first tape cartridge 201can optionally be disposed in a tape cartridge magazine 206 that, inturn, can then be disposed in the shelf system 220.

As shown in step 714, once a predetermined time has substantiallyelapsed from when the access occurrence was time stamped, the first tapecartridge 201 is loaded in either the first tape drive 224 or secondtape drive 222, such as by the transport unit 214, for example. Apredetermined function is something that is set, possibly by an end userprior to a selected event of action. The processor 241 is one optionaldevice that can account for elapsed time from when the access occurrencewas time stamped. Other clocks in the computer system or Computer AreaNetwork associated with the library 200 can optionally account forelapsed time from when the access occurrence was time stamped. Thelibrary 200, and more specifically the library's computer system, or thelike, can be set up with a predetermined time limit that can be inputtedby an operator via the GUI 218 to execute a user-specified action,which, in this example, is a data verification option. Hence, theauxiliary memory device 240, which maintains the MLM database, can bequeried by the processor 241, for example, to see when the first tapecartridge 201 substantially reaches the predetermined time limit.Optionally, the processor 241 can query the MLM database for all tapecartridges that possess an access occurrence time stamp and when theirrespective predetermined time limit has substantially been reached, therespective tape cartridge can be subject to the user-specified action.An operator can set the time limit via the GUI 218 wherein all the tapecartridges in the library 200 are on a schedule for data verification ona schedule, for example.

Once loaded, step 716 is a step for reading at least a portion of thedata including the new data residing on the first tape cartridge 201 (aportion can include a first and second stream of data separated by athird stream of data that is not assessed, or just a singular portion ofthe entire data stream stored on a tape medium, for example). This isfurther elaborated on in conjunction with FIG. 7C. For example, all ofthe data including the new data can be read (from the beginning of thetape media 102 to the end) or, optionally, only small portions of theold data and the new data can be read. The portions can be random or inknown intervals. Optionally, just file markers between data can be read.The tape medium can also be read at the beginning of the tape cartridgeand then at some point later on the tape cartridge.

Step 718 is a step for assessing whether the at least a portion of alldata contains a predictable, or expected, data structure devoid of anycomparison with a duplicate copy of such portion of all data. In anoptional embodiment, the predictable data structure is devoid of anycomparison of a representation of the at least a portion of all data,such as a hash function, for example (a hash function is typically amathematical function that converts a large, possibly variable-sizedamount of data into a small datum, usually a single integer that myserve as an index to an array). An expected data structure is thepredicted recorded structure of the data residing on the medium. Forexample, the residual magnetic impression of 1's and 0's retained in amagnetic medium can be sensed by a reading device and electricallyconverted into a signal that corresponds to the 1's and 0's. The orderof 1's and 0's corresponds to the content of the information stored onthe medium and the physical construct of the 1's and 0's, e.g., thesignature of a pulse corresponding to a 1, corresponds to the structureof the residual magnetic impression retained in the magnetic medium.Accordingly, the structure of the residual magnetic impression and/orthe approximate frequency of 1's and 0's are sufficient to determine theexistence of data and that the data is intact from a structural point ofview. Hence, an expected data structure of the digital information canbe determined by assessing, or analyzing, the structure of the data.Optionally, the rough, or approximate, distribution of 1's and 0's,which form the structure of digital data, can also be used to assess thegeneral health of the data on stored on the medium. If, for example, anaberrant distribution of 1's and 0's exist, e.g., just 0's or anoccasional 1, concern may be raised. Optionally, both the structure ofthe 1's and 0's and the approximate distribution of 1's and 0's can beused to assess an expected data structure and health of the media.Methods of assessing expected data structure include, among othertechniques, determining the number of read retries for both hard errors(data that cannot be read) and soft errors, errors that can berecovered, Error Code Correction techniques (ECC) typically associatedwith hard and soft errors, Pulse-Width 50 (PW-50) analysis, amplitudeanalysis, signal to noise ratio, or a combination of 2 or more of theaforementioned techniques, all of which are well known in the art. Thedata can be buffered and analyzed via an assessing technique, asdiscussed, to determine, or assess, if indeed the data exists asexpected or if the data is missing, degraded, or inconsistent with whatis expected. The analysis can be done by comparing a model of expecteddata outcome with the actual data read from the media. The expected dataoutcome can be all data falling within guidelines, such as upper andlower limits of acceptable outcomes. For example, if the ECC rate, ornumber of error code corrections in a given section of data, exceedswhat is considered a normal number, or rate, of corrections, the tapecartridge can be deemed a failed tape cartridge, that is, a cartridgethat is considered unreliable for storing data because it has reached apredetermined threshold of acceptable number of errors. This thresholdcan be calculated as a percentage of errors in a data set or simply araw number of errors, for example. Optionally, a drive vendor canprovide a command to determine the ECC rate, such as if the tapecartridge is read from end to end of the tape medium or just a portionthereon. The read data and error rates can be determined via aprocessor/s and algorithms (e.g., in the library CPU, for example) knownto those skilled in the art run thereon. Therefore, assessing the numberof hard and soft read errors, or the percentage of read errors, cantrigger a tape cartridge to be deemed a failure if the number isconsidered excessive, that is, exceeds a predetermined threshold of whatis considered acceptable of a properly/desirably/reliably functionaltape medium. Optionally, the assessment on the expected data structurecan be determined if an amount of the data fails to contain an expecteddata structure by frequency, degree, or other magnitude. The results ofthe data assessment can be stored in the library's auxiliary memory 240,for example, or in another storage location within the library.

Step 720 is a step for reporting whether or not the expected datastructure exists. That is, the results of the assessment can be reportedto an end user, a host 202, the GUI 218 associated with the library 200,a graphical display remote from the library 200, or some other locationthat can use the results. In the event the data of the first tapecartridge 201 is assessed to fall outside the guidelines of the expecteddata outcome, a warning can be issued to the end user, the host 202 orthe GUI 218, for example, that the first tape cartridge 201 isunreliable. Optionally, the results of the analysis can trigger thelibrary 200 to isolate the first tape cartridge 201, impose arestriction on any new data to be written to the first tape cartridge201, or attempt storage of duplicate data relative to the first tapecartridge 201 from a duplicate data source, such as a RAID system orsome other storage media that may contain duplicate data, discussed inmore detail in conjunction with FIG. 7C. Optionally, data from the firsttape cartridge 201 can undergo extreme data recovery procedures whereinany salvaged data can be stored onto a different (replacement) tapecartridge. The replacement tape cartridge can be mapped as the original,and the original can then be discarded. The replacement cartridge canassume some of the first tape cartridge's identity or essentially all ofthe first tape cartridge's identity, whichever is sufficient to beproperly mapped to a host. The library can automatically initiate a datarecovery sequence if the percentage or number or errors exceeds apredetermined threshold of allowable errors, for example. In an optionalembodiment, an end user can initiate the data recovery sequence. The enduser can input what the threshold or acceptable number or errors orpercentage of errors for a given portion of data can be.

Step 722 is a step for recording a second access occurrence on the MLMdata base and on the MAM 104 wherein the second access occurrencecorresponds to approximately when the assessing step 718 was performed.This step essentially resets the time for the next data assessment (dataverification) to repeat at a time interval set by an end user or thelike. Hence, an operator, for example, can input that one or more tapecartridges are to be assessed for data integrity every six months (justto pick an arbitrary amount of time) on the GUI 218 or an externalmonitor, or optionally a host 202 can set the time between dataintegrity assessments. Each tape cartridge 100 possesses a correspondingidentification, such as a serial number, maintained by the MLM data basewhich can be monitored to determine when each tape cartridge 100 isscheduled to be assessed for data integrity on a routine basis, such asevery six months to use the example above. Upon reaching the scheduledtime for data integrity assessment, a specific tape, such as the firsttape cartridge 201, proceeds to steps 714 through 722 and the process isrepeated.

In an optional embodiment, step 716 is accomplished by the first tapedrive 224 or second tape drive 222, or more specifically, processors andalgorithms running on the first tape drive 224 and second tape drive222. Optionally, step 718 is accomplished by the first tape drive 224 orsecond tape drive 222. Optionally, step 720 can be accomplished when thefirst tape drive 224 or second tape drive 222 sends the assessmentresults to the means for reporting, such as a display monitor or paperprinted by a printer, just to name several examples. Optionally, atleast steps 716 and 718 can be accomplished by the first tape drive 224or second tape drive 222.

FIG. 7B shows an optional embodiment of the present invention wherein arestriction is imposed for writing new data on the tape cartridge 201and a duplicate data source is used to replace the “unreliable” data.FIG. 7B is additive to FIG. 7A. As shown in step 720, if the tapecartridge 201 is deemed unreliable (e.g., a failed tape cartridge), itis restricted from storing any new data on the tape medium 102 thatresides therein. More specifically, if the data of the first tapecartridge 201 is assessed to fall outside the guidelines of the expecteddata outcome (for example, the data, or a portion thereof, on the tapemedium 102 of the tape cartridge 201 fails to meet a minimum specifieddata reliability level), the library 200 can execute a series ofinstructions, via the CPU 243, that takes the first tape cartridge 201off-line. A minimum specified data reliability level can be set via apredetermined limit. The predetermined limit, for example, can be apercent threshold of data having a data structure that deviates from theexpected/predicted data structure. The predetermined limit can berelated to how many read errors (hard and/or soft errors) were found ina given amount of data read. The predetermined limit can be arecommended limit set by a tape manufacturer, a library OEM, a host, oran end user that inputs the threshold in a program field displayed onthe GUI 218, just to name a few.

Assuming the first tape cartridge 201 is a failed tape cartridge, step722 is a step for searching for a duplicate copy of the data stored onthe failed first tape cartridge 201. The duplicate data may be stored ina RAID system or another data storage library, for example.

If a duplicate copy of the data (identical data) from the failed tapecartridge 201 is found, step 724 is a step for storing a copy of theduplicate copy of the data, in its entirety, to a replacement tapecartridge. The replacement tape cartridge can be remapped with any andall addresses or identifications associated with the failed tapecartridge 201 and disposed in the slot (in the shelf system 308)previously occupied by the failed tape cartridge 201. The failed tapecartridge 201 can “tagged” as failed by recording that it has a failedstatus on an MAM 104 disposed in the failed tape cartridge 201. Thisway, the failed tape cartridge 201 can be readily determined as a failedcartridge quickly and easily without necessarily loading the tapecartridge 201 in a tape drive 224. Furthermore, a record of the failedtape cartridge 201 can be maintained on a database, such as the medialifecycle management database kept on the auxiliary storage device 240.The failed tape cartridge can then be taken out of commission by removalfrom the library or disposal in a location in the library allocated forfailed tape cartridges.

One illustrative example of a reporting scheme, or layout, is shown inFIG. 8, which can report different levels of tape cartridge health. Asillustratively shown, the results of the assessment can be reported intable 800. A status field 801 can be blank 802 indicating that data hasnot yet been verified 810. The status field 801 can be labeled “green”804 indicating that the tape cartridge is in good shape wherein themedium is in good condition and/or the data is verified as being intact812. The status field 801 can be labeled “yellow” 806 indicating thatthe tape cartridge requires attention. For example, a yellow statusfield 806 may further provide information to the end user or operatorthat any new data writing should be stopped and the tape cartridgeshould be used only for data retrieval purposes 814. The status field801 can be labeled “red” 808 indicating that the tape cartridge isassessed as a failure 816. That is, the tape cartridge has been assessedas being in a failed condition and that transfer of any data should beto a new tape cartridge, not to the failed tape cartridge, and thefailed tape cartridge should be taken out of circulation. If the data onthe failed tape cartridge is the only data, attempts to transfer thedata from the failed tape cartridge to a good tape cartridge may be theonly option to save what data can be saved. Optionally, exceptionaltechniques, such as boosting signal output or applying special filtersmay be required to salvage the existing data on the failed tapecartridge. Optionally, tape cartridge health and percentage of errorscan be retained on the tape cartridge's MAM device and/or MLM database240.

In an optional embodiment, a tape cartridge can be read and verified aspossessing expected data signatures and, once verified, the data can beduplicated to another source, such as another tape cartridge, hard discdrive, or other storage media or storage device.

In an optional embodiment to the method discussed in steps 702-720, analgorithm running on a processor associated with the library 200, orelsewhere, can be configured to monitor all the tape cartridges in thelibrary 200 and anticipate when each tape cartridge will be scheduledfor data verification of the data on each respective tape cartridge.This can be accomplished by accessing the time stamp information of eachtape cartridge maintained in the MLM data base. Thus, an operator canset the time limit via the GUI 218 wherein all the tape cartridges inthe library 200 are on a schedule for being assessed for dataverification. The verification steps can be performed when the library200 is idle or during a scheduled downtime, such as during the night,for example.

In yet another embodiment of the present invention, data can be assessedimmediately after being written on the first tape cartridge 201.

In an optional embodiment, tape cartridge verification can be performedin a different drive than the drive from which data on a target tapecartridge was last stored. For example, with reference to FIG. 2A andFIGS. 7A and B, the first tape cartridge 201 is loaded in the first tapedrive in step 702. The data on the first tape cartridge 201 is laterassessed in step 716 on the second tape drive 222.

In yet another optional embodiment, the host 202 initiates and controlsthe tape verification method of FIGS. 7A and B. Optionally, a processorseparate from the host 202 initiates and controls the tape verificationmethod of FIGS. 7A and B. Optionally, the processor is part of thelibrary 200 (e.g., comprised by the library). Optionally, the processoris a Quad Interface Processor (QIP) produced by Spectra Logic Corp., ofBoulder, Colo. The QIP is substantially contained in the library 200. Inyet another optional embodiment, an agent other than the host 202 can beadded to initiate and control the tape verification method of FIGS. 7Aand B.

In another optional embodiment, a separate library, be it a tapelibrary, a disc drive library, a combination tape and disc drivelibrary, a solid state array library, or a like mass storage device thatpossesses mass storage capabilities, initiates and controls the tapeverification method of FIGS. 7A and B as an autonomous agent. Hence, afirst library functions as a master library instructing a secondlibrary, or slave library, to perform tape verification. In an optionalembodiment, the master library can control the specific functionalcommands associated with the tape verification steps of FIGS. 7A and B.

FIGS. 3A-3C are illustrations of a tape cartridge 201 being used inmultiple libraries. FIGS. 3A-3C can be used to describe an embodiment ofcoping with a time stamp on an MAM that is different from that which ismaintained in the MLM database when a tape cartridge is used indifferent libraries. As illustratively shown, in FIG. 3A the first tapedrive 224 in a first library 200 writs to a tape cartridge 201. A timestamp, or the point in time when the data was written on the tapecartridge 201, is recorded both on a MAM associated with the tapecartridge 201 and in the MLM data base maintained by the auxiliarystorage device 240. FIG. 3B shows the tape cartridge 201 being writtento in a second library 301. In one embodiment, the auxiliary storagedevice 240 receives knowledge from the second library 301 that the tapecartridge 201 has been written to and a time stamp update is recorded inthe MLM data base maintained by the auxiliary storage device 240. FIG.3C illustratively shows the tape cartridge being accessed in the firsttape drive 201 in the first library 300. In one embodiment, if the timestamp maintained by the MLM data base is different from that which isstored on the MAM in the tape cartridge 201 (e.g., the time stamp on theMAM is newer than the corresponding time stamp on the MLM database),then the MLM database will be updated with the time stamp correspondingto the MAM associated with the tape cartridge 201.

In yet another optional embodiment, tape verification can be performedwhile the library 200 is in full use via a global spare drive. Theglobal spare drive is discussed in detail in U.S. application Ser. No.12/407,919 which is incorporated herein by reference in its entirety. Aglobal spare drive is a spare drive in a library that is available as areplacement drive should an active drive be taken “off-line”. Becauseone or more global spare drives are idle, tape verification can beperformed in the background using global spare drives so as not tointerfere with the normal storage functions between a host computer anda library.

In one embodiment, tape drive use when verifying tape cartridges isbalanced between multiple drives to offset wear to any one specific tapedrive. For example, if there are four tape drives in a library, eachtape drive verifies about 25% of the tapes so that no single tape driveis doing the majority of the reading. Optionally, the tape drives areverifying data at substantially an equal amount of time over a specifictime period, such as a day, or a week, for example.

With reference back to FIG. 7C, a diagram is shown illustrating atypical layout of files saved on a section of tape medium 750 used in astorage system supporting tape media, such as the library 200. A tapelibrary generally stores data in a linear manner as instructed by thestreaming protocol from the host 202. Here, the data is stored on a tapemedium 750 in the form of files, such as File A 760 and File B 770separated by file markers 762. Herein, File A 760 and File B 770 areconfigured in a simplified construction. File A 760 comprises ninerecords 752, also known as logical data blocks, wherein each record 752comprises meta data 754 and user data 756. The data size of each record752 can be identical or, as shown here, variable for the entire file 760as exemplified by record zero 762 having a size of 50K bytes, record one764 having a size of 50K bytes, and record two 766 having a size of 100Kbytes. In a tape configuration, the files 760 and 770 and records 752generally run in sequential and contiguous order because of the linearaccess nature of tape. A host computer 202 using a streaming protocolgenerally makes data access requests for a storage system 200 in theform of files 760 and 770 and records 752 with commands, for examplespace forward so many files and space forward so many records (alsoknown as blocks in SCSI, Small Computer Systems Interface, protocol).The storage system 200 generally searches for a file, such as file A760, using file markers 762. For example, if a host 202 wanted to accessfile number fifty-two on a specific tape cartridge 201, for example, thetape cassette 201 containing the desired file number fifty-two would bescrolled forward from the beginning of the tape medium (not shown) andthe number of file markers 762 would be counted until file marker numberfifty-two was identified. If a host 202 wanted to access a record numberseventy-four in file number fifty-two then file number fifty-two wouldbe found as described and record number seventy-four would be found byreading the meta data 754 of one record 752 at a time sequentially untilrecord number seventy-four was found. A record 752 of interest can befound by scrolling the tape cartridge forward or backward as necessarybased on information about each record 752 stored in the meta data 754.

Hence, tape cartridges can be verified with different confidence levelssuch as if only a small portion of a tape cartridge tape medium isverified versus an entire tape cartridge tape medium. For example, theconfidence levels of data integrity diminishes as the potion of tapemedium assessed is reduced. Examples of portions of tape mediaassessments (such as assessed for errors) include only the beginningsegment of a tape medium, a first and second data stream are assessedwith a third data stream there between that is not assessed, etc. Astream of data is simply a portion of data that possesses least twobytes of data. Hence, a stream of data can be a logical data block 752,multiple data blocks 762 and 764, multiple files 760 and 770, etc. Inanother example, if only file marks 762 and meta data 754 are verifiedon a tape cartridge, or optionally, every 10 file marks 762 and metadata 754, the cumulative data on that tape cartridge can be assessed asperforming within specification with less confidence than a tapecartridge that is assessed entirely from the beginning of a tape mediumto the end of the tape medium. Other examples can include just assessingfile marks 762, random logical data blocks 754, logical data blocks 762and 776 separated by one or more data blocks 764 not assessed, etc. Theadvantages of assessing small samples of data dispersed across a tapemedium are time savings and wear to the drives, for example.

In another optional embodiment, some or all tape cartridges can bescanned and assessed, as described in conjunction with FIGS. 7A and B,before they are used for backup applications. For example, a company maybackup all storage in its main server at midnight every night. The tapecartridges that will be used for the backup can be assessed prior tobackup. As such, some tapes can be confirmed as blank, or having nodata, while others can be confirmed as possessing data. The onespossessing data can be overwritten or simply continued where the tapemedium is blank. The ones possessing data can be verified as in goodcondition; that is, they are capable of storing data with reasonableconfidence that the data stored thereon will be preserved. The resultscan be transmitted for the company to review.

In yet another aspect of the present invention, a tape cartridge can bedetermined to possess normal functionality prior to being used as abackup in what is essentially a pre-use verification. For example, atape cartridge possesses mechanical parts (or components) such as a tapemedium access door, locking mechanisms, at least one tape reel, leader,tape medium, just to name several mechanical parts. Though thesecomponents are assumed in working order when initially introduced in atape library, there may be some tape cartridges that are faulty causingcostly time delays when a host computer is attempting to store orretrieve data. In one embodiment, prior to ever using a tape cartridge,a pre-use verification can be performed to verify that a tape cartridgeis functional from a mechanical perspective. Optionally, pre-useverification can be performed at any time to assess mechanicalfunctionality of one or a group of tape cartridges. Furthermore, apre-use verification can determine if a tape cartridge used to storedata is indeed a tape cartridge used to store data and not a cleaningtape used for cleaning the heads on a tape drive. Moreover, a pre-useverification can determine that the tape cartridges being installed are,in fact, the appropriate tape cartridges usable with the library, forexample, capacity, tape model, drive compatibility, and the like.

Referring now to FIG. 9, shown therein is a block diagram illustratingmethod steps to practice an embodiment of pre-use verificationconsistent with embodiments of the present invention. It should berecognized that the steps presented in the described embodiments of thepresent invention do not necessarily require any particular sequenceunless otherwise specified explicitly. FIG. 2A is used in conjunctionwith FIG. 9 for purposes of illustration in the presently describedembodiment. The steps describe an embodiment consistent with the presentinvention of a method applicable to verifying the mechanics of tapecartridges and recording information on a cartridge's MAM 104, an MLMdata base, or both.

Step 902 shows a step for providing a library 200 with an entry and exitport 204, a first tape cartridge 201 wherein the first tape cartridge201 possesses a MAM 104, a MAM reader 230, 231, 232 and 234, a MAMwriter 230, 231, 232 and 234, a first tape drive 224 and a second tapedrive 222, a shelf system 220, and access to a memory device 240containing a Media Lifecycle Management (MLM) data base.

Step 904 shows a step for moving the first tape cartridge 201 into thelibrary 200 via the entry and exit port 204. The first tape cartridge201 can be one of a plurality of tape cartridges 100 that can beimported into the library 200 via the entry and exit port 204, such asby the tape cartridge magazine 206 used to support and mobilize multipletape cartridges 100. In one exemplary configuration, the tape cartridges100 can be placed in a holder (not shown) in the entry and exit port 204and moved between the shelf system 220 and the entry and exit port 204via the transport unit 214.

Step 906 shows a step for loading the first tape cartridge 201 in thefirst tape drive 224 from a tape cartridge magazine 206. This can beaccomplished right after the first tape cartridge 201 has beenintroduced into the library 200. Optionally, step 906 can beaccomplished when the first tape cartridge 201 is introduced to thelibrary 200 for the first time, the n^(th) time, or sometime after thefirst tape cartridge 201 has been introduced to the library 200. If thefirst tape cartridge 201 is “deemed” faulty, it can be replaced by aspare tape cartridge. The spare tape cartridge can be one of a pluralityof spare tape cartridges that are housed within the library in case atape cartridge fails to operate properly. The spare tape cartridge canbe one of a plurality of spare tape cartridges disposed in a magazine206 dedicated with spare tape cartridges. The spare tape cartridge thatreplaces a failed tape cartridge can be mapped with an address thatmakes the spare tape cartridge identifiable to the host computer 202.Hence, the replacement tape cartridge is identifiable to the hostcomputer 202 as the original tape cartridge that has since failed andbeen discarded. Any data that originally was stored on the failed tapecartridge can be stored to the replacement tape cartridge.

Step 908 shows a step for bringing the first tape cartridge 201 to afunctionally ready state with the first tape drive 224 such that thefirst tape cartridge 201 is operable to perform data exchangeoperations. A functional ready state is a state wherein the first tapecartridge 201 (or any tape cartridge) is adequately loaded in a tapedrive; that is, the tape cartridge 201 progresses through a series ofloading sequences to “come ready”, i.e., become operable to perform dataexchange operations. Generally, a tape cartridge 100 is inserted in anopening in a compatible tape drive, such as the first tape drive 224,Upon entering the tape drive, an arm mechanism associated with the tapedrive unlocks a spring-loaded latch associated with the tape cartridge100, thereby enabling another device associated with the tape drive toopen the tape medium access door. Spindle motor devices engage the reelor reels on which the tape medium is wound. In the case of a leader typetape structure, another mechanism associated with the tape drive graspsthe tape medium leader and threads the tape through drum devices andinto close proximity to tape heads associated with the tape drive usedto read and write data on the tape medium. Once fully loaded, the tapecartridge is physically arranged in a condition ready to store orretrieve data for a host.

Step 910 shows a step for assessing performance of the first tapecartridge 201 based on bringing the first tape cartridge 201 to afunctionally ready state. For example, some tape drives monitorsubstantially each task required to bring a tape cartridge to a readystate. In the event a tape cartridge fails to become functionally readyto perform data storage operations, an error code associated with thespecific portion, or step, of the loading sequence is generated. In somecircumstances, the error code is displayed by numbers and letterscorresponding to a specific error on an LED display, such as on an LTO-5tape drive from IBM Corp., of N.Y.

Step 912 shows a step for storing the results in one or more recordsfrom the assessment step of the first tape cartridge 201 on the MLM database maintained by the auxiliary storage device 240 and on the MAM 104associated with the first tape cartridge 201. The results of theassessment can correspond with an identifier associated with the firsttape cartridge 201 such a serial number, for example. The assessmentresults can include an identification of the tape drive that was usedduring the assessment, the date and/or time of the assessment, anidentification of the library that the tape cartridge was assessment in,and, optionally, other information beneficial to understandingparameters around the test such as temperature, power usage, humidity,and the like. If the tape cartridge passes the assessments, the tapecartridge 201 is verified “reliable” and the results can be indicated toan end user, such as through a display device associated with thelibrary 200 (the GUI 218) or a display device elsewhere. In other words,the tape cartridge 201 can be verified as “tested and functional” eitherindividually or by association with a larger group of tape cartridges100 that have all been verified as “tested and functional”. The passedtape cartridge 201 can then be mapped with an address so that a hostcomputer 202 can scan the library 200 and identify the tape cartridge201 as accessible for storage operations.

Step 914 shows a step for disposing the first tape cartridge 201 in alocation in the library 200, such as the shelf system 220, whichaccesses operable tape cartridges 100 if the first tape cartridge 201has passed the functional ready state. In an optional embodiment, thefirst tape cartridge 201 can be disposed in a magazine 206 that containsother functionally passed tape cartridges 100.

Step 916 shows a step for disposing the first tape cartridge 201 in alocation in the library 200 that at least temporarily holds inoperabletape cartridges 100, such as a designated shelf area 221 of the shelfsystem 220, if the first tape cartridge 201 has failed the functionalready state. In an optional embodiment, the first tape cartridge 201 canbe disposed in a magazine 206 that contains other failed tape cartridges100. The failed tapes can be those that a totally inoperable or to somedegree, inoperable. Optionally, tapes may be deemed inoperable it theyfail to meet a threshold of operability that may be set by an end user,tape drive OEM, or a host, for example. Performing in an expectedfunctional threshold is to perform according to pre establishedparameters wherein an end user, host, Original Equipment Manufacturer(OEM), for example, can set the parameters for which the readingperformance must meet at a minimum.

Step 918 shows a step for removing the first tape cartridge 201 from thelibrary 200 if the first tape cartridge 201 has failed. For example, allfailed tape cartridges 100 can be removed from the library 200, such asvia the exit port 204, to be analyzed or simply sent back to themanufacturer. The information of the failure criteria stored on the MAM104 of each tape cartridge 100 can provide information about the natureof the failure of the tape cartridge 100. The MLM data base can alsoprovide information about specific tape cartridge failures.

In an optional embodiment, the pre-use verification of the tapecartridges 100 can be performed with one or more global spare drives soas not to interrupt any on-going storage operations within a library.

In yet another aspect of the present invention, data integrity can beverified simultaneously on a tape cartridge while the data thereon isduplicated to a different storage device, such as a tape, disc drive,flash memory or the like.

FIG. 10 is a block diagram of two tape library systems 1000 and 1030that can be used illustratively to show embodiments of tape cartridgeverification and data duplication. The first library 1000 possesses afirst tape drive 1004 and a third tape drive 1006, both of which have aMAM reader and writer device 1018, a processor device 1016, an auxiliarystorage device 1014, a plurality of tape cartridges 100 disposed in ashelf system 1008, and a graphical user interface 1002. The tapecartridges 100 can be transferred into and out from the first library1000 via an entry and exit port 1020. Also shown loaded in the firsttape drive 1004 is a first tape cartridge 1010, used herein forillustrative purposes. The second library 1030 possesses a second tapedrive 1034 and a fourth tape drive 1036, both of which have a MAM readerand writer device 1018, a processor device 1046, an auxiliary storagedevice 1044, a plurality of tape cartridges 100 disposed in a shelfsystem 1038, and a graphical user interface 1042. The tape cartridges100 can be transferred into and out from the second library 1000 via anentry and exit port 1032. Also shown loaded in the second tape drive1034 is a second tape cartridge 1012, used herein for illustrativepurposes.

Referring now to FIG. 11, shown therein is a block diagram illustratingmethod steps to practice an embodiment of tape cartridge verificationduring data duplication consistent with embodiments of the presentinvention. It should be recognized that the steps presented in thedescribed embodiments of the present invention do not necessarilyrequire any particular sequence unless otherwise specified explicitly.FIG. 10 is used in conjunction with FIG. 11 for purposes of illustrationin the presently described embodiment. The steps describe an embodimentconsistent with the present invention of a method applicable toverifying data on a tape cartridge when at least a portion of datastored therein is transferred to a different tape cartridge. The methodmaintains results and other information related to the data verificationon a cartridge's MAM 104, an MLM data base, or both. The MLM data basecan be maintained by an auxiliary storage device 240 as shown in FIGS.1A and 2A.

Step 1102 shows a step for providing a first library 1000 having a firsttape cartridge 1010 wherein the first tape cartridge 1010 possesses afirst MAM (not shown), a MAM reader 1018, a MAM writer 1018, a firsttape drive 1004, a shelf system 1008, and access to an auxiliary memorydevice 1014 containing a first Media Lifecycle Management (MLM) database.

Step 1104 shows a step for providing a second library 1030 having asecond tape cartridge 1012, possessing a second MAM (not shown), a MAMreader 1018, a MAM writer 1018, a second tape drive 1034, a shelf system1038, and access to an auxiliary memory device containing 1014 a secondMedia Lifecycle Management (MLM) data base.

Step 1106 shows a step for loading the first tape cartridge 1010 in thefirst tape drive 1004. This can be accomplished with a robotic transportdevice, such as the transport unit 214 of FIG. 2A, for example.

Step 1108 shows a step for loading the second tape cartridge 1012 in thesecond tape drive 1034.

Step 1110 shows a step for transferring at least a portion of datastored on the first tape cartridge 1010 to the second tape cartridge1012. Data can be transferred between the first tape library 1000 andthe second tape library 1030 via a direct connection or through anintermediary, such as a host or server, for example. The at least aportion of data can range from a small fraction of the total datamaintained on the first tape cartridge 1010 to the total data maintainedon the first tape cartridge 1010. Transferring the at least a portion ofdata can be initiated by either the first library 1000 or the secondlibrary 1030, a host, such as the host 202 of FIG. 2A, a command inputon one of the GUI's 1002 or 1042 by an operator, a scheduled datatransfer/duplication, or an automatic initiation when a newer generationtape cartridge is introduced to either the first library 1000 or thesecond library 1030, just to name several examples for promptinginitiating data transfer.

Step 1112 shows a step for assessing whether the at least a portion ofdata contains an expected data signature devoid of any comparison with aduplicate copy of the at least a portion of data or a representation ofthe at least a portion of data (e.g., content analysis). That is, theassessing of data does not rely on comparing the content of known orduplicate data to the data being assessed; rather, expected datasignatures or error rates indicating the presence of data is all that isassessed, as discussed in conjunction with FIGS. 7A and B.

Step 1114 shows a step for recording an access occurrence to the firstand second MLM data base and on the first and second MAM wherein theaccess occurrence corresponds to approximately when the assessing step912 was performed. This step essentially resets the time for the nextdata assessment (data verification) on the first MAM associated with thefirst tape cartridge 1010 to repeat at a time interval set by an enduser or the like and sets the time that can be used for the next dataassessment for the second tape cartridge 1012. Details of recordingaccess occurrences are discussed in more detail with regard to FIGS. 7Aand B.

Step 1116 shows an optional step for storing a record of the duplicationof the at least a portion of data to the first and second MLM data base,maintained by the respective first and second auxiliary storage devices1014 and 1044, and on the first and second MAM (not shown). For example,information indicating that the first tape cartridge 1010 has beenduplicated can be stored to the first tape cartridge's MAM and the firstlibrary's MLM data base. Likewise, information indicating that thesecond tape cartridge 1012 possesses duplicated data can be stored tothe second tape cartridge's MAM and the second library's MLM data base.

Step 1118 shows yet another optional step for recording a firstidentification associated with the first tape cartridge 1010 to thesecond MAM and recording a second identification associated with thesecond tape cartridge 1012 to the first MAM wherein both of theidentifications are associated with indicia that paired data exists onboth the first and the second cartridges 1010 and 1012. Paired datarefers to an original version of data and a duplicate of the originalversion data. Hence, the duplicate data is paired with the originaldata. The first identification can be, for example, a tape cartridgeserial number that is recorded to the second tape cartridge's MAM(contained in the second tape cartridge 1012) that ties or indicates,the duplication event with the first tape cartridge 1010 (or the eventof duplicating a portion of the data). The second identification isrecorded to the first tape cartridge's MAM and ties or indicates, theduplication event with the second tape cartridge 1012. Hence, recordscan be stored on each of the tape cartridge's respective MAMs linkingthem to common data in which they all had possession (e.g., all the tapecartridges have stored there on a copy of at least some of the samedata). Both the first MLM data base maintained by the first auxiliarymemory device 1014 and the second MLM data base maintained by the secondMAM device 104 can retain a record of the duplication event, the time ofthe event occurrence, and identities of all tape cartridges, in thiscase the first tape cartridge 1010 and the second tape cartridge 1012,that contain paired data. In an optional embodiment, the duplicate datacan be transferred to and stored on three or more tape cartridges. Thus,the aforementioned steps can be subtly adjusted to accommodate three ormore tape cartridges. In yet another embodiment, data verification(e.g., sampling read errors) can be performed on a tape mediumtransferring data in the simple duplication of data from one tape mediumto another and a record made to each respective MAM device.

Step 1120 shows a step for reporting whether or not the predictable datasignature exists. That is, the results of the assessment can be reportedto a host, one or both of the GUI's 1002, 1042, a graphical displayremote from the libraries 1000 and 1032, or some other locationaccessible to those that would utilize the results. In the event thedata of the first tape cartridge 1010 is assessed to fall outside theguidelines of the expected data outcome, a warning can be issued to theend user that the first tape cartridge 1010 is unreliable and that thedata duplicated on the second tape cartridge 1012 came from a failedtape cartridge. Optionally, the results of the analysis can trigger thelibrary 1000 to isolate the first tape cartridge 1010, impose arestriction on any new data to be written to the first tape cartridge1010 and search for a duplicate data source. Optionally, if the firsttape cartridge 1010 fails in the assessment, a replacement tapecartridge 100 can be made within the first (or second) library 1000,thus, maintaining a validated paired data. Optionally, data from thefirst tape cartridge 1010 can undergo extreme data recovery procedureswherein any salvaged data can be stored on both the second tapecartridge 1012 and on a third tape cartridge.

The second tape cartridge 1012 well as the first tape cartridge 1010 canbe set to proceed through the data assessment procedures of stepsassociated with FIGS. 7A and B, thereafter.

Optionally, the above steps can be accomplished with solely the firsttape library 1000 using the first drive 1004 and the second drive 1006.

Embodiments of the present invention can be commercially practiced in aSpectra Logic T-950 tape cartridge library manufactured by Spectra Logicof Boulder Colo. FIG. 11 shows a commercial embodiment of one T-950library unit 1200 without an enclosure. The T-950 library 1200 comprisesa first and second shelf system 1230 and 1240 that are adapted tosupport a plurality of the mobile media, such as the tape cartridgemagazine 206 comprising a plurality of LTO-3 tape cartridges with MAMs,archived by the library 1200. The shelf systems 1230 and 1240 can eachcomprise at least one auxiliary memory reader, such as the auxiliarymemory reader 232 of FIG. 2A. Disposed next to the second shelf system1240 are at least four IBM LTO-3 drives adapted to write data to andread data from a tape cartridge. The IBM LTO-3 drives each have thecapability of storing data to an auxiliary radio frequency memory device104 contained in an LTO-3 cartridge. Functionally interposed between thefirst and second shelf system 1230 and 1240 is a magazine transportspace 1210. The magazine transport space 1210 is adapted to provideadequate space for a tape cartridge magazine 206 to be moved, via amagazine transport and cartridge picker (not shown), from a position inthe first shelf system 1230, for example, to a drive. The magazinetransport and picker can further accommodate at least one auxiliaryradio frequency memory device reader, such as the reader 234 from FIG.2A. Tape cartridge magazines 206 can be transferred into and out fromthe T-950 library 1200 via an entry/exit port 1250. Transferring tapecartridge magazines 206 in and out of the T-950 library 1200 can beaccomplished by an operator for example. The T-950 library 1200comprises a means for cooling as shown by the fans 1260, located at thebase of the library 1200. The T-950 library 1200 can be linked to acentral data base, such as the data base 602, wherein the central database can provide storage of all of the auxiliary radio frequency memorydevices, such as the device 104, contained in each tape cartridge in theT-950 library 1200 as read by any one of the auxiliary radio frequencymemory device readers. The T-950 library also comprises a librarycontroller (not shown) that can function as the processor device 241 inaddition to an auxiliary storage device 240, such as a disk drive (orplurality of disk drives), of FIGS. 3A-3C. The T-950 library 1200 alsoprovides a graphical user interface (not shown) whereon a display ofassessment results or, in an alternative embodiment, simple messagespertaining a user-specified action associated with a tape cartridge, canbe displayed, such as an alert accompanying a sound alarm orrecommendations for further action/s, for example.

It is to be understood that even though numerous characteristics andadvantages of various embodiments of the present invention have been setforth in the foregoing description, together with the details of thestructure and function of various embodiments of the invention, thisdisclosure is illustrative only, and changes may be made in detail,especially in matters of structure and arrangement of parts within theprinciples of the present invention to the full extent indicated by thebroad general meaning of the terms in which the appended claims areexpressed. For example, multiple, or all tapes in a library, can bemanaged in the tape validation process for example, while stillmaintaining substantially the same functionality without departing fromthe scope and spirit of the present invention. Another example caninclude using these techniques across multiple library partitions, whilestill maintaining substantially the same functionality without departingfrom the scope and spirit of the present invention. Further, thoughcommunication is described herein as between a client and the library,such as the library 201, communication can be received directly by adrive, such as the first drive 218, via the interface device 230, forexample, without departing from the scope and spirit of the presentinvention. Further, for purposes of illustration, a first and seconddrive and tape cartridges are used herein to simplify the descriptionfor a plurality of drives and tape cartridges. Finally, although thepreferred embodiments described herein are directed to tape drivesystems, such as the tape cartridges and tape storage systems, such as atape library and tape drives, and related technology, it will beappreciated by those skilled in the art that the teachings of thepresent invention can be applied to other systems, without departingfrom the spirit and scope of the present invention.

It will be clear that the present invention is well adapted to attainthe ends and advantages mentioned as well as those inherent therein.While presently preferred embodiments have been described for purposesof this disclosure, numerous changes may be made which readily suggestthemselves to those skilled in the art and which are encompassed in thespirit of the invention disclosed and as defined in the appended claims.

What is claimed is:
 1. A method for certifying data on tape cartridges,the method comprising: providing a library with: a first tape cartridgepossessing a medium auxiliary memory device; a medium auxiliary memorydevice reader; a medium auxiliary memory device writer; a first tapedrive and a second tape drive; a shelf system; and a system adapted toaccess a memory device containing a media lifecycle management database; loading said first tape cartridge in said first tape drive;writing new data on said first tape cartridge after said loading step;recording a first access occurrence corresponding to approximately whensaid writing step was performed; unloading said first tape cartridgefrom said first tape drive; disposing said first tape cartridge in saidshelf system after said unloading step; loading said first tapecartridge in one of said first or said second tape drives after apredetermined time has elapsed from said first access occurrence;reading a second portion of said new data residing on said first tapecartridge, said second portion sequentially follows a first portion;assessing said second portion to determine data integrity, said firstportion is not assessed for said data integrity; and initiating a datarecovery sequence if said data integrity fails to meet an acceptablelevel of an expected data structure.
 2. The method of claim 1 whereinsaid first access occurrence is recorded on said media lifecyclemanagement data base and on said medium auxiliary memory device.
 3. Themethod of claim 1 wherein said first portion is sequentially between athird portion of said new data and said second portion of said new data,wherein said third and said second portions are assessed and said firstportion is not assessed.
 4. The method of claim 1 wherein said secondportion is a second logical data block separated from a third logicaldata block by said first portion which corresponds to at least onelogical data block, wherein said second and said third logical datablocks are assessed and said first portion is not assessed.
 5. Themethod of claim 1 wherein said portions consists of file marks.
 6. Themethod of claim 1 wherein said portions essentially excludes user data.7. The method of claim 1 further comprising storing a record of saiddata integrity assessment on at least one of said medium auxiliarymemory device and said media lifecycle management data base.
 8. Themethod of claim 1 wherein said data recovery sequence includes restoringessentially all of said data to a replacement tape cartridge.
 9. Themethod of claim 1 further comprising transmitting to and end userdifferent levels of tape health notification according to differentlevels of assessed data integrity.
 10. A method for certifying dataretained by a tape cartridge in a tape library, the method comprising:providing a first portion of data that sequentially precedes a secondportion of data retained on a tape medium comprised by said tapecartridge; reading said second portion of said data at a scheduled time;assessing a degree to which said second portion of data contains anexpected data structure wherein said first portion of data is notassessed; and reporting, via a display device, to an end user if saiddegree falls below a predetermined threshold.
 11. The method of claim 10further comprising executing a data recovery action of said data if saidexpected data structure falls below said predetermined threshold. 12.The method of claim 11 wherein said data recovery action includesrestoring essentially all of said data to a replacement tape cartridge.13. The method of claim 10 wherein said second portion is a secondstream of data separated from a third stream of data by said firstportion of data, wherein said third and said second streams of data areassessed and said first portion of data is not assessed.
 14. The methodof claim 10 wherein said degree is based on the percentage of saidsecond portion of data that contains said expected data structure andfurther comprising the step of reporting different tape health statusesaccording to different values of said percentage.
 15. The method ofclaim 10 further comprising the steps of comparing data content.
 16. Amethod for certifying data, the method comprising: providing a librarywith a tape drive and a tape cartridge, said tape cartridge possessestape medium with data retained thereon; loading said tape cartridge insaid tape drive; reading a second portion of said data that is precededby a first portion of said data; assessing a percentage of errors fromreading said second portion of data wherein said first portion of saiddata is not assessed, and wherein said assessing is accomplished withoutcomparing data content; and executing a data recovery action of saiddata if said percentage of errors exceeds a predetermined threshold. 17.The method of claim 16 wherein said data recovery action includesrestoring essentially all of said data to a replacement tape cartridge.18. The method of claim 16 wherein said second portion is a secondstream of data separated from a third stream of data by said firstportion of data, wherein said third and said second streams of data areassessed and said first portion of data is not assessed.
 19. The methodof claim 16 further comprising storing a record of said percentage on amedium auxiliary memory device located essentially in said tapecartridge, an media lifecycle management data base associated with saidlibrary, or both said medium auxiliary memory device and said medialifecycle management data base.
 20. The method of claim 16 furthercomprising transmitting to an end user different levels of tape healthnotification according to different levels of assessed percentages.